Abstract: Objective:To investigate the anti-tumor effect of cytotoxic T lymphocytes (CTLs) activated by dendritic cells (DCs) pulsed with K-ras antigen. Methods:DCs were generated from PBMC in the presence of GM-CSF and IL-4 in vitro. DCs were sensitized with pancreatic cancer cell line expressing K-ras mutant，K-ras (12-Val) mutant peptide, K-ras ( 12-Val) mutant peptide with the surface of cationic nanoparticle. The mature DCs were cocultured with autologous T cells to obtain antigen specific CTL. The anti-tumor activity of CTL in vivo was evaluated in BALB/c nude mice bearing Patu 8988(K-ras+) and SW 1990 (K-ras-) pancreatic cancer. Results: CTLs cocultured with DCs with the whole tumor antigen significantly inhibited the growth of transplanted pancreatic cancer (Patu 8988 and SW 1990) in nude mice. In vivo experiments showed that DCs with K-ras ( 12-Val) mutant peptide and K-ras mutant peptide with the surface of cationic nanoparticle induced killing activity of specific CTL aganist pancreatic cancer cell line Patu 8988(K-ras+) ( P<0.05). Conclusion:CTL induced with DCs pulsed with K-ras antigen can significantly improve the survival of nude mice with pancreatic cancer, through inhibiting tumor growth.